The present invention relates to a control of an internal combustion engine and more particularly to throttle valve control means.
In conventional automobile engines, throttle valves are actuated by means of foot pedals which are connected with the throttle valves through linkages or cable mechanisms so that movements of the foot pedals are transmitted to the throttle valves. It should however be noted that the conventional structures are disadvantageous in that where the linkages are adopted the mechanisms become very complicated and there required many connections which inherently have plays so that the movements of the foot pedals cannot be rapidly transmitted to the throttle valve. Where the cable mechanisms are adopted, the cables must be maintained under tension to prevent slackening of the cables, and due to the cable tension and friction developed in the mechanisms, substantial efforts are required for operating the throttle valves.
In order to eliminate the above problems, there has been proposed throttle valves operated by electric actuators. For example, the Japanese patent application No. 50-62408 filed on May 23, 1975 and disclosed for public inspection on Nov. 29, 1976 under the Disclosure No. 51-138235 discloses an engine throttle valve control means including an operating member position detector for detecting the position of a throttle valve operating member such as a foot pedal, a throttle valve position detector for detecting the actual position of throttle valve and a control circuit which receives electric signals from the operating member position detector and the throttle valve position detector to produce an output which is used to operate a reversible actuator for actuating the throttle valve in accordance with the position of the throttle valve operating member. In the mechanism proposed by the Japanese patent application, however, the throttle valve actuator is always operating substantially at a predetermined rate so that the throttle valve cannot be opened with a satisfactory responsive rate even when the operating member is moved very quickly to an open position for rapid acceleration.